The government is expected to wrap up its high-profile insider trading case against former Goldman Sachs director Rajat Gupta today following a second round of testimony from Goldman Sachs CEO Lloyd Blankfein.

Gupta stands accused of leaking confidential information to his hedge-fund pal Raj Rajaratnam when Gupta was serving on the boards of Goldman and Proctor & Gamble.

One tip, according to the charges, is Warren Buffett’s $5 billion investment in Goldman at the height of the financial crisis, which sent Goldman’s stock soaring.

Blankfein, the highest-profile government witness, told the jury on Tuesday that Gupta was not authorized to disclose Buffett’s investment.

Gupta’s lawyers, who could start their case this afternoon, have lined up at least 15 witnesses, many of whom are expected to testify to the character of the former head of McKinsey & Co., potentially including Gupta’s eldest daughter and Ajit Jain, head of several of Buffett’s reinsurance businesses.

The highlight of yesterday’s court action had nothing to do with evidence or testimony.

Rather, it dealt with a third-year student at Cardozo Law School. The 24-year-old student was pulled from the gallery and was asked to speak privately with the judge, prosecutors and defense lawyers.

It turned out the student, Benula Bensam, had been expressing her opinions of the case in letters she sent to Judge Jed Rakoff.

The judge wanted her to stop.

Bensam told reporters during the lunch break that Rakoff was concerned about “undue influence.”

She said US Marshals “misconstrued” her intentions two days earlier, when she had refused to answer their questions.